That’s the same as any early access game I suppose. They tend to release one chapter a year. The next one is imminent, though likely Q1 next year and it’s the largest chapter yet. I’d recommend picking it up on the next sale regardless.
I’ve been gaming on Tumbleweed now for a month and my issues are minor enough that a tweak or two gets me flawless performance - and that’s if there’s an issue. Highly recommend embracing the penguin, comrades.